The invention relates to apparatus for applying a liquid onto a moving web, preferably a web of paper. In particular, the invention is concerned with such apparatus which is one of the type comprising at least one rotatable roller arranged to contact the moving web at one peripheral location; an appliance for supplying the liquid to the roller periphery or jacket; and a roller wiper having a rotatable wiper rod, which can be pressed by biasing means onto the roller jacket, which is located between the supply appliance and the peripheral contact location and arranged to extend across the width of the web for dispensing the liquid as a layer to move with the roller jacket towards said web.
Apparatus of this type can be arranged within or externally of a paper manufacturing machine, for example. The liquid to be applied can be a glue suspension, for example, within which the web of paper is impregnated, i.e. the glue suspension penetrates more or less completely within the web of paper. However, the liquid can also be a coating mass, such as pigment deposits of all sorts from which a color or a protective layer is formed on the web of paper. In both cases the liquid may be applied to one side of the web of paper or on both sides of the web of paper.